A Non parametric equivelent to mixed anova?


I am trying to find a non-parametric equivalent to a mixed Anova? My data is horrible. Three small unequal groups (8, 8, 4) and data which is not equally distributed. I am trying to compare the effect of two different interventions with control) over a 3 different time periods on a range of dependent variables.

Thanks for any one who can point me in the right direction,